[Eosinophilic esophagitis associated with recurrent urticaria: is the worm Anisakis simplex involved?]

Anisakis simplex, a fish parasite of the nematode family, typically infects marine mammals such as whales, dolphins and seals. Human anisakiasis, which is acquired by eating raw or insufficiently heated fish or squid, has gained world-wide importance. Infestation with living larvae caused by eating parasitised fish results in acute upper abdominal pain, nausea and vomiting and may be confused with acute abdomen due to appendicitis and other inflammatory abdominal disorders. Extraintestinal organ manifestations are rare. Endoscopically, inflammation, oedema, erosions and ulcerations may be found. The parasite can been found in up to 50% of patients. Histologically, an eosinophilic inflammation is typical. Acute anisakiasis may be prevented by thorough cooking or deep-freezing the parasitised fish for at least 48 h. IgG-antibodies specific for Anisakis simplex are thought to represent an immunological host reaction against parasitic antigens. More recently, allergic reactions to Anisakis ingestion or exposure, such as urticaria, anaphylaxis and even occupational asthma, have been reported. These allergic reactions may also occur when the fish has been properly cooked, and hence these allergens are thought to be heat-stable. Such cases may be diagnosed by skin tests and the determination of specific Anisakis-IgE. However, the specificity of IgE is low, since they may also be present in exposed asymptomatic individuals. Since the eliciting allergens are temperature-stable, prophylactic dietetic measures are indicated. We report a case from Switzerland acquired during a holiday in Portugal. The patient suffered from recurrent dysphagia and urticaria, and histologically eosinophilic oesophagitis was found. IgG-antibodies and a positive skin prick test to Anisakis simplex support its aetiologic role for the symptoms.